People's reliance on various electronic devices increases with the constant progress in the electronic technology. It is known that internal electronic elements of various electronic devices, such as desktop computers, notebook computers and the like, will produce a large amount of heat during operation thereof. The produced heat must be timely guided off the electronic devices to avoid overheating of the electronic device. Therefore, most electronic devices are internally provided with a cooling fan for the devices to always operate at a predetermined working temperature.
Please refer to FIGS. 1A and 1B. A serial fan 1 known in the electronic industrial field includes a plurality of size-identical fan frames 10, a plurality of fan wheels 11 and a motor (not shown), which are assembled together to form the serial fan 1. When the serial fan 1 operates, it produces vibration as a result of the motor's operating torque. The conventional serial fan 1 is formed by serially connecting the fan frames 10 to one another via a fastening structure 12 provided on between any two adjacent fan frames 10. More specifically, the conventional serial fan 1 is formed by serially assembling a plurality of fan frames 10 in a direction parallel to a central axis thereof. With this assembling method, it is not able to change the serial fan's vibrating state. When the fan wheels 11 in the fan frames 10 rotate simultaneously, the vibration frequencies of the fan wheels 11 influence one another to induce a serious resonance effect between the fan frames 10. The vibration caused by this resonance effect is directly propagated from the fan frames 10 to other electronic elements of the electronic device, on which the serial fan 1 is mounted, such as the highly vibration-sensitive hard disk drive in a computer unit of the electronic device. Moreover, since the fan frames 10 in the conventional serial fan design are respectively formed as one single part, they are not able to effectively reduce the fan vibration. In some worse condition, the vibration produced by the motor and the fan wheels 11 would interfere with the normal operation of other electronic elements, preventing the whole system of the electronic device from reaching its best performance. Another disadvantage of the conventionally assembled serial fan 1 is that the resonance effect between the fan frames 11 also brings loud noise.
In brief, the prior art serial fan assembling method has the following disadvantages: (1) failing to effectively reduce the fan vibration; (2) being unable to eliminate noise caused by fan vibration; and (3) largely lowering the system hard disk drive access efficiency.
It is therefore tried by the inventor to develop an improved serial fan assembling method to eliminate the above-mentioned disadvantages.